Method of sulfating materials.



H. B. HOVLAND & G. B. FRAN KFORTER. METHOD or SULFATING MATERIALS.

APPLICATION .HLED MAY 28. 19|-5. I

Patented Nov. 2, 1915.

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H. .B. HOVLAND & G. B. FRANKFORTER. METHOD OF SULFATIING MATERIALS.

APPLICATION FILED MAY 28. I915.

1,159,033, Patfited Nov. 2, 1915.

2 SHEETSSHEET 2- N f 9 2" /L J /9 20 //X I 24 I I Q a! I IIIIIIIHIIIJIEI may be herein briefly stated as for the i .NRY B. HOVLAND, or DULUTH, AND GEORGE ii.

FRANKFORTEB, or MINNEAPOLIS,

MINNESOTA; SAID FRANKFOBTER ASSIGNOR T0 SAID HOVLAN'D.

METHOD OF SULFATING MATERIALS.

Specification of Letters Patent.

Application filed May 28, 1915. Serial No. 31,030.

To all whom it may concern Be it known that we, HENRY B. HOVLAND and GEORGE B. FRANKFORTER, citizens of the United States, residing at Duluth, county of St. Louis, and Minneapolis, county of Hennepin, Minnesota, respectively, have invented certain new and useful Improvements in Methods of Sulfating Materials {and we do hereby declare the following to be a full, clear, and exact description of the nvention, such as will enable others skilled in the art to which it appertains to make and use the same. a

This invention relates to the method of sulfating ores and other materials in the manner disclosed in our co-pending application, Serial No. 28,308, filed May 15, 1915.

In said co-pending application, a method of sulfating is disclosed, which consists in bringing together under super-atmospheric pressure, the material to be sulfated, a sulfur-yielding substance such as sulfurous acid or iron pyrite and oxygen chemically available for reaction, such as pure oxygen or the oxygencontained in air. The purpose of sulfating under super-atmospheric pressure is set forth in detail in the accompanying' application above referred to, but

purpose of promoting the reaction between the constituents and increasing the yield of the sulfated material.

The present application is directed specifically to the wet method of sulfating in the manner above set forth, and consists, in its preferred form, in first mixing the comminuted material to be sulfated with water to form a pulp, and then bringing together under super-atmospheric pressure, the pulp vso formed, a sulfur-yielding substance and available oxygen. This is preferably done by supplyingeither or both the sulfur-yielding substance and available oxygen under superatmospheric pressure. During the reaction, the pulpis agitated or stirred and a circulation of the gases, which may be either the available oxygen, sulfur-yielding substance, or both, is maintained-through the pulp during its agitation. I

The improved process may be carried out in any suitable form of apparatus, but to give a clear understanding ofthe process,

one form of apparatus is herein illustratedand described.

The apparatus. itself forms the subjectthe This tube is matter of a co-pending application of Henry B. Hovland, Serial N 0. 31,898, filed June 3, 1915.

The apparatus is illustrated in the aceonr panying drawings, in 'which:

Figure 1 is a side elevation of the apparatus; and Fig. 2 is a vertical central section of apparatus shown in Fig. 1. eferring to the drawings, it will be noted that the apparatus comprises an outer metallic casing 1 having a cover 2 rigidly bolted thereto by means of the bolts 3, in order to render the casing capable of'withstanding relatively high internal pressure. ed within the casing 1 is a container 4, preferably in the form of a glass jar having a square cross section. 'The container 4 is suspended by means of metallic hangers 5 secured to the cover 2 and depending within the casing. Projecting into the interior of the container 4 is a hollow rotatable stem 6 closed at its upper end and carrying at its lower portion, an agitator 7 of the type disclosed in another co-pending application'of Henry B. Hovland, Serial N9. 31,899, filed June 3, 1915.

The specific construction of the agitator 7 need notbe herein described, but it should be noted that the head of the agitator comprises two spaced plates having radial vanes positioned therebetween to form radial pas- I 2 and provided with a valve 13. The tube 12 is connected to a flexible tube 1 1- which is adapted to discharge into a sampling adapted to be connected to material supply or to the source of .sulfurous acid'supply. A second tube 16 extends through the cover 2 and projects over the opening of the container 4. provided with a controlling valve 17. f

Patented. Nov. 2, 1915.

Suspendwhich extends nearly to the container. At a point outside the tube 11 is connected v with a tube 12 extending through the cover The entire apparatus above described,

' with the exception of the motor, is mounted upon a suitable supporting structure denoted generally by the reference character 18. For this purpose, transverse supporting members 19 are bolted to the'cover 2 and bear upon the supporting structure 18, as clearly shown in both Figs. 1 and 2. Leveling screws 20 may serve to support the members 19 on the supporting structure 18, if so desired.

When it is desired to disassociate the cover 2 from the casing 1, the bolts 3 are loosened and then the rotatable threaded hangers 21 are rotated by means of the handles 22, and the casing 1 is lowered through the intermediary of the radially-extending portions 23 secured to the casing ,1 and having threaded engagement with the hangers 21. The hangers 21 are rotatably mounted in the supporting members,19, so it will be obvious that rotation of the hangers produces relative movement between the casing and its cover.

The bottom part of the casing 1 tapers toward a discharge valve 24, beneath which is placed any suitable receptacle, such as that shown at 25. In one side of the casing is positioned an electric are :producing plug 26 supplied with current through a suitable electric conductor 27, and at the other side of the casing is positioned a combined pres With..the interior of the casing through the' sure and vacuum gage 28 communicating pipe 29. The pipe 29 communicates with a tube 30 controlled by means of a valve 31. If desired, the cover 2 may be provided with a sight-glass 31 through which the operations in the casing may be viewed. An electric bulb 32 may be positioned in the easing to illuminate its interior and may be connected by means of the electrical con ductors 33 to a source of current supply.

The motor 10, above referred to, is pref-' erably mounted upon a sleeve 34 which, in turn, is slidably mounted upon one of the uprights 35 of a supporting frame. A second sleeve 36 is slidably .mounted upon a second upright 37, and the two sleeves 36 and 34 are interconnected by means of a cross member 38, so that the said sleeves and the cross member 38 may slide in unison upon the uprights 35 and 37. Each of the extremities of the cross member 38 has threaded engagement with the adjacent and 40 will cause a sleeve, as shown at 39 and 40, respectively. When the cross members, 38 is rotated in either direction, the'threaded extremities 39 l longitudinal movement of the cross member, 11 one direction or the other, thereby causing one of .the extremities of the cross member to bind against either the upr ght 35; or 37, thereby locking the whole slidable frame comprising the sleeves 34 "and 36-and the cross member 38 in place.

To facilitate the rotation of the cross member 38, a suitable handle 41 rnay be pro vided. It will be noted from Fig. 1 that the uprights 35 and 37 are supported by means of the transverse members 42 and 43 rigidly secured to the supporting structure 44 at 45 and 46, respectively. The lower transverse member 43 serves to support a filling funnel 51. In. order to facilitate the movements of the frame to which the motor 10 is attached, the weight of said frame and motor may be counterbalanced by means of a counter-weight 47 connected to the frame by means of a rope or cord 48 passing over the pulleys 49 and 50.

In utilizing an apparatus as above described for carrying out the process, the tube 16 is first connected to a vacuum pump and 'a partial vacuum created in the casing 1.

The flexible tube 14 is then connected with the funnel 51. The valve 17 is then closed and the comminuted ore or other material to be-sulfated, which has been previously mixed with the desired quantity of water, is poured slowly into the funnel 51. The valve 13 is then opened to permit the pulp poured into the funnel to be drawn into the container 4. The valve 13 is then closed and the flexible tube 14 is connected to .the source of supply of the sulfur-yielding substance,

valve 17 is opened, it is obvious that the available oxygen is supplied to the casing under super-atmospheric pressure. The available oxygen is preferably under a pressure of 30 to 100 pounds to the square inch, so that the pressure maintained in the easing-1 is in the vicinity of 30-to 100 pounds to the square inch- As the beater or agitator 7 is rapidly rotated, it impels the pulp with whichlit comes into contact outwardly causing a partial vacuum to be created in the vicinity" of the beater, which draws the available oxygen, and any other gases present in the casing, through the openings 9 and down through the hollow. stem 6. It is then delivered through theopenings 8 in the agitator head to the pulp and passes upwardly there through in the'form of bubbles.- The oxygen'not absorbed and utilized for reaction inkits travel through the pulp escapes from a the top or the container ,4" and is again drawn downwardly tlirough'the openings 9 and the hollow [stem 6. In this way, a circulation of the oxidizing medium is maintained through the pulp While said medium is under super-atmospheric pressure. As the oxidizing agent passes through the pulp in the presence of sulfurous acid, the chemical reactions take place, which result in the sulfating of the metallic values of the ore.

As the oxygen is consumed through reaction, the valve 31 is partially opened to permit bleeding, which results in fresh air or available oxygen in other form, passing into the casing through tube 16 and valve 17. By thus leaving the valve 31 partially open. and valve 17 open and by connecting the tube 16 to a source of oxygen supply under constant pressure, it is obvious that the desired pressure may be maintained in the casing 1 and still have a constant supply of fresh available oxygen.

Samples may be taken from the apparatus at intervals by closingthe valve 17 and reducing the pressure in the casing through the valve 31 to about 5 pounds above atmospheric pressure, and then While the agitator 18 is still in operation, opening the valve 13, thus permitting the required amount of sample to be forced through the flexible tube 14 into the sampling beaker 15. After the sample has been obtained, the valve 13' is closed and the valve 17 again opened, whereby the pressure is again raised to the original point. It is obvious that if the sample taken indicates a deficiency of sulfurous acid, or any other ingredients used, they may be supplied through the tube 14.

The reaction may be augmented by means of any suitable catalyst, such as sodium chlorid and the like. In the present instance, an electric are produced by the plug 26 serves to generate oxids of nitrogen to act as the catalytic agent. hen the reaction is completed and it is desired to remove the charge, valve 17 is closed and the pressure in the casing is reduced through valve 31 to about 5 pounds above atmospheric pressure. The valve 31 is then closed and the valve 13 opened, thus permitting the charge, While being agitated through the continued rotation of the agitator, to be forced out through the flexible tube 14: into a suitable vessel provided for the purpose of collecting the charge. It is obvious that wash Water may be introduced in the container at to clean out the last portion of the.

charge, if so desired. The valve 2 is for the purpose of draining the casing 1 when the same contains any material to be discharged and the receptacle 25 receives the material discharged through the valve 2i.

From the foregoing, it will be 'seen that in its preferred form, the process consists in forming a pulp of the material to be sulfated, and then bringing together the pulp so oi-med, a sulfur yielding substance and available oxygen under super-atmospheric pressure, and that the available oxygen under super-atmospheric pressure is circulated through the pulp while the latter is under violent agitation. The super-atmospheric pressure greatly promotes the reactions between the oxygen, as it is circulated through the pulp, and the sulfur-yielding substance which is brought into the presence of the pulp and the available oxygen,

In the preferred form of the process, the application of external heat is not necessary as the process may be carried out at ordinary temperature. Heat may be generated by the reaction, but, nevertheless, as no pre-. caution need be taken to supply other heat than that automatically generated, it is true that the process under such circumstances is carried out at ordinary temperature. 'As the application of heat is unnecessary, it permits the use of a permanent gas oxidizing agent, such as air, pure oxygen, etc., instead of steam, which is not a permanent gas, steam having been formerly used Where heat is necessary.

The wet method of sulfatingabove described has been found especially valuable in treating copper-bearing ores, to sulfate the copper and recover the same in the form ofcopper sulfate. For the treatment of copper ores, it has been found that sulfurous acid constitutes the best sulfur-yielding substance and that air under super-atmospheric pressure constitutes the best medium for supplying the available oxygen. thermore, in the treatment of copper ores and ores closely related thereto, Water has been found to be the best medium for Wetting the comminuted ore. to form a pulp thereof, but it is obvious that in the treat ment of other substances, it may be desirable to use some liquid other than Water. The term pulp as used herein is intended to designate any material capable of being treated in the manner set forth when Wetted by a suitable quantity of Water or other liquid, and, therefore, in using the term pulp, We do not Wish to limit ourselves to the combination. of comminuted ore and Water.

What We claim is Fur- 1. The'method of sulfating, Whichconpressure to augment the reaction the pulp so formed, sulfurous acid and available oxygen.

The method of sulfating which consists in. adding liquid to the material to be sulfated to form a pulp and subjecting the pulp at ordinary temperature and under sutlicient superatmospheric pressure to augmentthe reaction, to the action of a permanent gas oxidizing agent in the presence of available sulfur.

4. The method of sulfating, which consists in adding liquid to the material to be sulfated to form a pulp thereof, and passing available oxygen at ordinary temperature and under sufficient super-atmospheric pressure to augment the reaction through the pulp While the pulp is in available sulfur 5. The method of sulfating, which consists in adding liquid to the material to'be sulfated to form a pulp, bringing together under sulficient super-atmospheric pressure to augment the reaction the pulp so formed, a sulfur-yielding substance and oxygen chemically available for reaction, and augmenting the reaction by agent. 7

6. Thejamethod of sulfating Which consists'in adding liquid to the material to be the presence of means of a catalytic and circulating a and air through the pulp, the sulfurous acid and air being under suificient superatmospheric to augment the reaction.

7, The method of sulfating Which consists inadding liquid to the material to be sulfated to form a pulp, and circulating a mixture of sulfurous acid and air through the pulp, the sulfurous acid and air being at ordinary temperature and under sufficient superatmospheric pressure to augment the reaction.

8. The method of sulfating which consists pressure in fated to form a pulp and circulating an oxidizing agent, at'ordinary temperature and at sufficient superatmospheric pressure to augment the reaction, through the pulp While the pulp is in the presence of available sulfur.

In testimonv whereof tures.

We aifix our signa- HENRY B. HOVLAND. GEORGE B. FRANKFORTER.

(,opies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. 0.

adding liquid to the material to be sul-' 

